Clutch releasing mechanism for automatic lathes



Nov. 14, 1939.

CLUTCH RELEASING MECHANIS-1 FOR AUTOMATIC LATHES Filed A l il 5, 1958 2 Sheets-Sheet l 'IIIIIIIIIII/I,

H. JUNGHANS 2.179.744

Nov. 14, 1939.

CLUTCH RELEASING MECHANISM FOR AUTOMATIC LATHES Filed April 5, 1938 2 Sheets-Sheet 2 Hezvrwf JL-nyigrw .y

.7/Wen/ar d H. JUNGHANS 2.179.744

Patented Nov. 14, 1939 srrss CLUTCH RELEASING MECHANISM FOR AU- TOMATIC LATHES Helmut Junghans, Schramberg- Sulgen, Germany Application April 5, 1938, Serial No. 200,274 In Germany December 14, 1936 8 Claims.

This invention relates to automatic lathes and to clutch-releasing means for the spindle, and more particularly the thread-cutting spindle, of lathes of this kind.

It is the object of the invention to provide a highly sensitive releasing means, i. e., a releasing means which responds to extremely light pressure on the part of the control element and performs the de-clutching action in a fraction of a second.

The high sensitivity with which it is desirable that the releasing means should be permitted to act is of the utmost importance in the cutting of extremely fine threads, which may pcssibly comprise merely one single turn. At the same time, however, the sensitivity of the releasing means should not be brought about in any manner which may prove detrimental to the reliability of the release.

A releasing means fulfilling the conditions aforesaid is furnished in accordance with the invention with a pawl and ratchet mechanism for holding the coupling lever in the coupling position, a hammer for releasing the said pawl and ratchet mechanism, and a further pawl and ratchet mechanism, which is released by a feeling member on the spindle and holds the hammer in the striking position. The said parts cooperate in such a manner that by means of cams at first the hammer is moved into the striking position and then the coupling lever into the coupling position, there then being initiated the action on the piece of work, whereupon at the end of the operation the feeling member releases the pawl for the hammer, and this in turn releases the pawl for the coupling lever, and the clutch disc is braked.

In order to shorten as far as possible the time required for the release of the clutch, i. e., to make the release sudden in its action, the coupling lever, in accordance with an additional feature of the invention, comprises two interengaging parts, which are shiftable to a limited extent in parallel fashion in relation to one another in the plane of the lever, and between which there is provided a spring, which is tensioned upon the coupling operation. The part of the lever acted upon in direct fashion by the control cam co-operates with the coupling pawl, and upon the release of the latter is moved with sudden movement, under the action of the relaxing spring, towards the second part of the lever engaging with the clutch disc, whereby in turn the clutch is also released with sudden movement.

According to another feature of the invention, independent control elements are provided for engaging the clutch and for carrying out the actual operation on the piece of work.

Additional features of the invention relate 5 to the peculiar form of the two-part coupling lever and the embodiment of the hammer and its locking elements.

There will be described by way of example an embodiment of the invention in its application to releasing means for the spindle of the threadcutting device of an automatic lathe. The accompanying drawings illustrate the invention in different stages of the operation.

Fig. 1 is a view, partially in section, of the clutch and associate parts of the automatic lathe according to the invention, wherein the hammer has been moved into the striking position and the hammer pawl is in engagement with the notched slide. The coupling is disengaged.

Fig. 2 is a view similar to Fig. 1 in which, for the sake of better comprehension, the hammer and its pawl have been omitted, and which shows the clutch in the engaged position.

.Fig. 3 is a similar view showing the condition in which the feeling member on the threadcutting spindle releases the hammer pawl, the hammer in turn is released by the clutch pawl, and the clutch disc is pressed against the brake disc.

Fig. 4 is an end View of the coupling lever.

Fig. 5 is a side view partly in section of the coupling lever.

Fig. 6 is a side view partly in section of an extension arm.

Fig. '7 is an end view of the extension arm.

Fig. 8 is a sectional View of the recess in the extension arm.

The arrangement of the releasing means is as follows: a is the thread-cutting spindle of an automatic lathe. b is the body of the lathe, and c is the driving disc for the spindle a. The spindle is driven by way of the clutch disc 11. This clutch disc carries in the conventional manner a neck ring 011, which is engaged by the coupling lever 5 e. Opposite the driving disc 0, taken in relation to the clutch disc, there is provided the fixed brake disc 1, which cooperates with the clutch disc by way of the brake surface g. The coupling lever e is a two-armed lever, the fulcrum of 50 which is situated at e Its extension arm e co-operates by way of a roll with the control cam h on the cam disc 2'. The coupling lever e engages with its stub e in a slot-like recess e in the extension arm e the slot 6 permitting of 55 so much clearance that the two parts of the lever are able to perform a limited parallel displacement in relation to one another. Between the one face e of the slot and the lever stub there are fitted two springs k. These are compressed when the face or jaw 6 upon the coupling action is moved towards the stub.

When the springs k relax the side or jaw e of the slot is moved against the stub with sudden movement. The object of this peculiar construction of the coupling lever will be obvious from the later description of the operation of the complete device. The extension arm .2 is also furnished with a notch e which engages with the coupling pawl Z when the clutch is engaged. The coupling pawl is pivoted at 1 It also possesses an arm 1 against which there bears the pawl spring m, and a second arm 1 the object of which will be described later.

There will now be described the releasing means for the coupling pawl Z. These means comprise a four-armed lever n, which for the purpose of the present description has been termed a hammer (Figs. 1 and 3). The long arm 11 controls by way of a slot guide the notched slide 0, which is shiftable in a straight line in a guide In the nose of the slide there is cut a notch 0 It co-operates with the hammer pawl p, which is mounted at p and is acted upon by a tension spring q. The hammer pawl p also possesses an arm 11 which, as feeling arm, cooperates with the feeling disc 1 on the thread-cutting spindle and carries the adjustable feeling pin 10 The feeling disc r is mounted firmly on the threadcutting spindle and is displaced in agreement with the cutting tool.

The second arm 11?, which is short in relation to the first arm n is engaged by the hammer striking spring 3. The reason for the selection of this ratio between the length of the arm n and that of the arm 11. is due to the fact that it is necessary to have the least possible pressure of engagement between the slide 0 and the hammer pawl pl, so that the release of this locking means can take place with negligible force.

The third arm n of the hammer co-operates with the control cam t on the cam disc i. The control cam 25 moves the hammer into the striking position. The cams h and t are adjustable .in relation to one another and to the threadcutting curve.

The fourth arm n of the four-armed lever n is the actual hammer. It carries a hammer pin 19, and with this pin it strikes against the extension arm l of the coupling pawl l.

There having been explained the general arrangement of the parts there will now be described the manner in which the parts co-operate as a Whole. This will be done on the basis of the three positions illustrated in Figs. 1 to 3:

1st p0sz'ti0n.--Fig. 1. The clutch d is disengaged. The thread-cutting spindle a is pressed towards the left under the action of the spring u. The clutch disc is pressed with its brake surface 9 against the brake disc 1 by a spring 1) located inside the spindle. The control cam 15 has just moved the hammer n into the striking position, and the hammer spring s is tensioned.

The hammer pawl p has entered the notch o in the slide 0 and is in the position of readiness.

The cam disc 2' continues to rotate, and the cam h moves the coupling lever towards the coupling position.

2nd position-The coupling lever e is in the coupling position. Upon the movement into this position the coupling springs It provided in the slot guide 6 between the extension arm e and the stub e have been compressed. The coupling pawl 1, under pressure of the pawl spring m, has been moved into the notch e in the extension arm. The thread-cutting spindle a is now advanced for the thread-cutting operation.

3rd p0siti0n.The thread has been cut. The feeling disc 1 has moved against the feeling pin 19 of the feeling arm p The hammer pawl 10 has been rocked out of the notch o in the notched slide. In this way the hammer n has been released to perform its striking action. Under the action of the contracting spring s the hammer pin 11 on the arm n has been caused to strike against the extension arm Z of the coupling pawl l and to lift the latter out of the notch e in the extension arm e of the coupling lever. The extension arm 6 thus released has been moved towards the stub e by the springs 70 provided between the sam'e and the said stub, in such a manner as to cause the jaw e of the slot guide to strike within sudden movement against the stub e In this manner the clutch d, c has been suddenly disengaged, and the spring 12 provided within the spindle has been able to move the clutch disc against the brake disc f and thus immediately stop the thread-cutting spindle. The entire releasing operation takes place in a fraction of a second.

The thread-cutting spindle is then withdrawn and the operation is able to proceed anew.

What I claim as new and desire to secure by Letters Patent is:

1. In a releasing means for the spindle clutch of an automatic lathe, a coupling lever, means for holding the said lever in the coupling position, a hammer for releasing the said leverholding means, means for holding the said hammer in the striking position, control cams which move the said hammer into the striking position and thereupon the said coupling lever into the coupling position, and means in association with the spindle of the lathe for releasing the said hammer-holding means after action on the piece of work, whereupon the said hammer releases the said lever-holding means to brake the clutch disc.

2. In a releasing means for the spindle clutch of an automatic lathe, a coupling lever, a pawl for holding the said lever in the coupling position, a hammer for releasing the said pawl, a second pawl for holding the said hammer in the striking position, a feeling member on the spindle of the lathe for releasing the said second pawl, and control cams which move the said hammer into the striking position and thereupon the said coupling lever into the coupling position, whereupon following action on the piece of work the said feeling member releases the said second pawl holding the hammer and the said hammer releases the said first pawl holding the coupling lever to brake the clutch disc.

3. In a releasing means for the spindle clutch of an automatic lathe, a coupling lever comprising two interengaging parts which are shiftable to a limited extent parallel to one another in the plane of movement of the said lever, and a spring between the said parts of the said lever, the said spring being compressed when the clutch is engaged, a pawl co-operating with one of the parts of the said lever to hold the said lever in the coupling position, the second part of the said lever co-operating with the clutch disc of the said clutch, a control cam acting on the said first part of the lever, and means for releasing the said pawl after action on the piece of work, the said first part of the lever upon release of the said pawl being moved by the said spring with sudden movement against the said second part of the lever for the purpose of suddenly releasing the clutch.

4. In a releasing means for the spindle clutch of an automatic lathe, a coupling lever comprising a stub and an extension arm, a slotted guide in which the said stub is guided with sufiicient clearance to permit of a limited parallel displacement of the said stub in the plane of movement of the lever, the said guide forming part of the said extension arm, a pawl adapted to engage in a notch in the said extension arm, springs disposed between the said stub and the said guide and adapted to be compressed when the clutch is engaged, and means for releasing the said pawl after action on the piece of work, the said springs thereupon relaxing and causing the said stub to be moved with sudden movement against the opposite side of the said guide for the purpose of suddenly releasing the clutch.

5. In a releasing means for the spindle clutch of an automatic lathe, a coupling lever, a pawl for holding the said lever in the coupling position, a hammer comprising four arms, a notched slide controlled by one of the said arms of the hammer, a feeling member on the spindle of the lathe, a hammer pawl co-operating with the said feeling member and adapted to engage in the notch in the said slide, a striking spring engaging with the second arm of the said hammer, the third arm of the hammer co-operating with the said hammer pawl, and an extension arm on the said lever-holding pawl adapted to be struck by the fourth arm of the said hammer.

6. In a releasing means for the spindle clutch of an automatic lathe as claimed in claim 5, a hammer comprising four arms, a notched side controlled by one of the said arms of the hammer, and a striking spring engaging with another of the arms of the said hammer, the said arm acting on the said slide being long in relation to the said arm acted upon by the said spring.

7. In a releasing means for the spindle clutch of an automatic lathe having a brake disc for braking the clutch disc after release of the clutch, a coupling lever, means for holding the said lever in the coupling position, a hammer for releasing the said lever-holding means, means for holding the said hammer in the striking position, control cams which move the said hammer into the striking position and thereupon the said coupling lever into the coupling position, means in association with the spindle of the lathe for releasing the said hammerholding means after action on the piece of'work to disengage the clutch, and a spring in association with the said spindle to press the clutch disc against the brake disc after the clutch has been disengaged.

8. In a releasing means for the spindle clutch of an automatic lathe, a coupling lever, means for holding the said lever in the coupling position, a hammer for releasing the said lever-holding means, means for holding the said hammer in the striking position, control cams which move the said hammer into the striking position and thereupon the said coupling lever into the coupling position, a striking spring for the hammer, and means in association with the spindle of the lathe for releasing the said hammer-holding means after action on the piece of work, whereupon the said hammer releases the said lever-holding means to brake the clutch disc.

HELMUT JUNGHANS. 

